Jim
As much as I like gratuitous girders and truss work, in the second bridge which you are mocking up, the supporting arch is underneath the box, so there is absolutely no need for a second supporting arch as in the first bridge.
So arches over top with suspension cabling plus supporting arches beneath would be too many arches.
The box bridge with the arches beneath is simple and matches nicely with your stone arches.
But a suspension bridge like in the first pic would be stunning and give an interesting counterpoint to the aforementioned arches.
James